It's a "two strike" technique, guys... and while it's not necessarily lethal, it hurts like hell and can be fatal. The first strike is across the hollow at the base of the eyebrows to actually break the cartlidge loose... the second strike is up and in, pushing the tip of the nose to the hollow just below the eyebrows, where you made the first hit.
No, I've never killed anybody with it, but the technique (when not tried simply as a one-strike technique) has all the indications that it would work. If you drive it into the frontal lobe, you end up giving the guy a lobotomy just to get it back out.
By the way, I've ALWAYS trained it as a two strike technique... not just a punch.